Regular and switching platform: Bone stress analysis with varying implant diameter

The aim of this study was to evaluate stress distribution of the peri-implant bone by simulating the biomechanical influence of implants with different diameters of regular or platform switched connections by means of 3-dimensional finite element analysis. Five mathematical models of an implant-supported central incisor were created by varying the diameter (5.5 and 4.5 mm, internal hexagon) and abutment platform (regular and platform switched). For the cortical bone, the highest stress values (rmax and rvm) were observed in situation R1, followed by situations S1, R2, S3, and S2. For the trabecular bone, the highest stress values (rmax) were observed in situation S3, followed by situations R1, S1, R2, and S2. The influence of platform switching was more evident for cortical bone than for trabecular bone and was mainly seen in large platform diameter reduction.

Aspectos históricos e implicações da utilização do efeito 3D no cinema: o caso de A invenção de Hugo Cabret

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Application of two segmentation protocols during the processing of virtual images in rapid prototyping: ex vivo study with human dry mandibles

The aim of this study was to evaluate the accuracy of virtual three-dimensional (3D) reconstructions of human dry mandibles, produced from two segmentation protocols (outline only and all-boundary lines).Twenty virtual three-dimensional (3D) images were built from computed tomography exam (CT) of 10 dry mandibles, in which linear measurements between anatomical landmarks were obtained and compared to an error probability of 5 %.The results showed no statistically significant difference among the dry mandibles and the virtual 3D reconstructions produced from segmentation protocols tested (p = 0,24).During the designing of a virtual 3D reconstruction, both outline only and all-boundary lines segmentation protocols can be used.Virtual processing of CT images is the most complex stage during the manufacture of the biomodel. Establishing a better protocol during this phase allows the construction of a biomodel with characteristics that are closer to the original anatomical structures. This is essential to ensure a correct preoperative planning and a suitable treatment.

Desenvolvimento de aplicações Web com base em modelagem 3D: módulo Android

This project brings the development of an Android application which will allow users to access 3D models on web. The application developed allows Android devices to access web pages which have code that should use OPENGL to renderize. To demonstrate this functionality, an example web application was build, using technologies such as X3DOM and HTML5, which uses WebGL to get renderized. This web application gives to the user an environment of a virtual city, where he could surf by and interact with the objects. The Android application brings this immersion to the mobile world, also. The access and storage of data was developed a Webserver, which bring to the web application a simple API to give access to the database

Desenvolvimento de um Game para Android O S

With the technology advancement, mobile devices have become increasingly more powerful and have started to have functions beyond of making phone calls. New applications, which perform these new functions, have been launched. The digital entertainment market has become one of the most benefited with this, once the games have become one of the most used applications for various types of users. This monograph presents the development of a game for Android OS, considering concepts like: physics, scenarios/views and character animation

Diagnóstico e planejamento em cirurgia parendodôntica: utilização da tomografia cone beam

The ability to tridimensionally evaluate pathological and anatomical areas, in apical surgery planning, presents a number of advantages. Cone beam computed tomography (CBCT) was developed for dental applications. This paper aims to present a literature review on CBCT, highlighting its advantages over both conventional computed tomography (CT) and radiography. Moreover, its clinical applications in apical surgery are discussed. LITERATURE REVIEW AND CONCLUSION: Unlikely CT, CBCT captures a volume of data in a single 360º rotation, providing benefits such as higher accuracy, better resolution, reduced scanning time and reduced radiation dose. In the maxillofacial region, CBCT has been mainly used in the assessment of dento-alveolar pathology and oral traumatology. CBCT provides a better diagnosis and quantitative information on periodontal bone levels than conventional radiography. It has also been used for patients requiring surgical facial reconstruction, orthognathic surgery, dental implants, and more complex tooth extractions. Besides that, it seems to be a significant tool in modern endodontic practice, presenting useful applications in apical surgery.

Assessment of variations of the mandibular canal through cone beam computed tomography

The neurovascular bundle may be vulnerable during surgical procedures involving the mandible, especially when anatomical variations are present. Increased demand of implant surgeries, wider availability of three-dimensional exams, and lack of clear definitions in the literature indicate that features of anatomical variations should be revisited. The objective of the study was to evaluate features of anatomical variations related to mandibular canal (MC), such as bifid canals, anterior loop of mental nerve, and corticalization of MC. Additionally, bone trabeculation at the submandibular gland fossa region (SGF) was assessed and related to visibility of MC. Cone beam computed tomography exams from 100 patients (200 hemimandibles) were analyzed and the following parameters were registered: diameter and corticalization of MC; trabeculation in SGF region; presence of bifid MC, position of bifurcations, diameter, and direction of bifid canals; and measurement of anterior loops by two methods. Corticalization of the MC was observed in 59% of hemimandibles. In 23%, MC could be identified despite absence of corticalization. Diameter of MC was between 2.1 and 4 mm for nearly three quarters of the sample. In 80% of the sample trabeculation at the SGF was either decreased or not visible, and such cases showed correlation with absence of MC corticalization. Bifid MC affected 19% of the patients, mostly associated with additional mental foramina. Clinically significant anterior loop (> 2 mm of anterior extension) was observed in 22-28%, depending on the method. Our findings, together with previously reported limitations of conventional exams, draw attention to the unpredictability related to anatomical variations in neurovascularization, showing the contribution of individual assessment through different views of three-dimensional imaging prior to surgical procedures in the mandible.

Radiation dose optimized lateral expansion of the field of view in synchrotron radiation X-ray tomographic microscopy

Volumetric data at micrometer level resolution can be acquired within a few minutes using synchrotron-radiation-based tomographic microscopy. The field of view along the rotation axis of the sample can easily be increased by stacking several tomograms, allowing the investigation of long and thin objects at high resolution. On the contrary, an extension of the field of view in the perpendicular direction is non-trivial. This paper presents an acquisition protocol which increases the field of view of the tomographic dataset perpendicular to its rotation axis. The acquisition protocol can be tuned as a function of the reconstruction quality and scanning time. Since the scanning time is proportional to the radiation dose imparted to the sample, this method can be used to increase the field of view of tomographic microscopy instruments while optimizing the radiation dose for radiation-sensitive samples and keeping the quality of the tomographic dataset on the required level. This approach, dubbed wide-field synchrotron radiation tomographic microscopy, can increase the lateral field of view up to five times. The method has been successfully applied for the three-dimensional imaging of entire rat lung acini with a diameter of 4.1 mm at a voxel size of 1.48 microm.

MRI monitoring of cartilage repair in the knee: a review

Various treatment options for deep cartilage defects are presently available. The efficacy of bone marrow stimulation with microfracture, of mosaicplasty and of various autologous chondrocyte implantation (ACI) techniques has been subject to numerous studies recently. Magnetic resonance imaging (MRI) has gained a major role in the assessment of cartilage repair. The introduction of high-field MRI to clinical routine makes high resolution and three-dimensional imaging readily available. New quantitative MRI techniques that directly visualize the molecular structure of cartilage may further advance our understanding of cartilage repair. The clinical evaluation of cartilage repair tissue is a complex issue, and MR imaging will become increasingly important both in research and in clinical routine. This article reviews the clinical aspects of microfracture, mosaicplasty, and ACI and reports the recent technical advances that have improved MRI of cartilage. Morphological evaluation methods are recommended for each of the respective techniques. Finally, an overview of T2 mapping and delayed gadolinium-enhanced MR imaging of cartilage in cartilage repair is provided.

Open issues in transcatheter aortic valve implantation. Part 1: patient selection and treatment strategy for transcatheter aortic valve implantation.

An exponential increase in the use of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis has been witnessed over the recent years. The current article reviews different areas of uncertainty related to patient selection. The use and limitations of risk scores are addressed, followed by an extensive discussion on the value of three-dimensional imaging for prosthesis sizing and the assessment of complex valve anatomy such as degenerated bicuspid valves. The uncertainty about valvular stenosis severity in patients with a mismatch between the transvalvular gradient and the aortic valve area, and how integrated use of echocardiography and computed tomographic imaging may help, is also addressed. Finally, patients referred for TAVI may have concomitant mitral regurgitation and/or coronary artery disease and the management of these patients is discussed.

Cone beam computed tomography (CBCT) for diagnosis and treatment planning in periodontology: A systematic review.

OBJECTIVE The improvement in diagnostic accuracy and optimization of treatment planning in periodontology through the use of three-dimensional imaging with cone beam computed tomography (CBCT) is discussed controversially in the literature. The objective was to identify the best available external evidence for the indications of CBCT for periodontal diagnosis and treatment planning in specific clinical situations. DATA SOURCES A systematic literature search was performed for articles published by 2 March 2015 using electronic databases and hand search. Two reviewers performed the study selection, data collection, and validity assessment. PICO and PRISMA criteria were applied. From the combined search, seven studies were finally included. CONCLUSION The case series were published from the years 2009 to 2014. Five of the included publications refer to maxillary and/or mandibular molars and two to aspects related to vertical bony defects. Two studies show a high accuracy of CBCT in detecting intrabony defect morphology when compared to periapical radiographs. Particularly, in maxillary molars, CBCT provides high accuracy for detecting furcation involvement and morphology of surrounding periodontal tissues. CBCT has demonstrated advantages, when more invasive treatment approaches were considered in terms of decision making and cost benefit. Within their limits, the available data suggest that CBCT may improve diagnostic accuracy and optimize treatment planning in periodontal defects, particularly in maxillary molars with furcation involvement, and that the higher irradiation doses and cost-benefit ratio should be carefully analyzed before using CBCT for periodontal diagnosis and treatment planning.

Ocean bottom seismometer sgy-files of refraction seismic profiles from Professor Logachev cruise TTR16/3

Over the last decade pockmarks have proven to be important seabed features that provide information about fluid flow on continental margins. Their formation and dynamics are still poorly constrained due to the lack of proper three dimensional imaging of their internal structure. Numerous fluid escape features provide evidence for an active fluid-flow system on the Norwegian margin, specifically in the Nyegga region. In June-July 2006 a high-resolution seismic experiment using Ocean Bottom Seismometers (OBS) was carried out to investigate the detailed 3D structure of a pockmark named G11 in the region. An array of 14 OBS was deployed across the pockmark with 1 m location accuracy. Shots fired from surface towed mini GI guns were also recorded on a near surface hydrophone streamer. Several reflectors of high amplitude and reverse polarity are observed on the profiles indicating the presence of gas. Gas hydrates were recovered with gravity cores from less than a meter below the seafloor during the cruise. Indications of gas at shallow depths in the hydrate stability field show that methane is able to escape through the water-saturated sediments in the chimney without being entirely converted into gas hydrate. An initial 2D raytraced forward model of some of the P wave data along a line running NE-SW across the G11 pockmark shows, a gradual increase in velocity between the seafloor and a gas charged zone lying at ~300 m depth below the seabed. The traveltime fit is improved if the pockmark is underlain by velocities higher than in the surrounding layer corresponding to a pipe which ascends from the gas zone, to where it terminates in the pockmark as seen in the reflection profiles. This could be due to the presence of hydrates or carbonates within the sediments.

AVALIAÇÃO POR MEIO DE MODELOS VIRTUAIS TRIDIMENSIONAIS DAS DISTÂNCIAS INTERCANINOS E INTERMOLARES INFERIORES EM TRÊS MOMENTOS

O propósito desse estudo foi de avaliar a estabilidade do tratamento ortodôntico em três momentos distintos, por meio de mensuração das distâncias intercaninos e intermolares inferiores, utilizando, como ferramenta, modelos virtuais tridimensionais. Foram selecionados modelos de gesso da arcada inferior de 19 pacientes em três fases distintas: pré-tratamento (T1), pós-tratamento (T2) e mínimo de 5 anos pós-contenção (T3), totalizando 57 modelos, os quais foram digitalizados por meio do Scanner 3D SCANTEH ST500 (SCAN technology A/S, Dinamarca), para obtenção dos modelos virtuais tridimensionais. Nesses modelos virtuais tridimensionais foram selecionadas e mensuradas as distâncias entre as pontas de cúspide dos caninos, denominada distância intercaninos e pontas de cúspide mesiovestibulares dos primeiros molares, denominada distância intermolares, com o auxílio do programa Rapidform ( Inus Technology Inc,). Para a análise estatística, foi realizada a análise de variância de medidas repetidas, e realizadas comparações múltiplas de Bonferroni ao nível de significância de 5%. As distâncias intercaninos e intermolares, em média, diminuíram entre T1-T2 e continuaram diminuindo entre T2- T3. Após 4 semanas, 20% da amostra foi novamente mensurada para avaliação do erro do método, onde foram encontrados valores médios semelhantes aos encontrados na primeira mensuração. Nesse trabalho, utilizando-se modelos virtuais tridimensionais, nota-se que não há estabilidade durante e após o tratamento ortodôntico, no tocante às distâncias intercaninos e intermolares.

AVALIAÇÃO POR MEIO DE MODELOS VIRTUAIS TRIDIMENSIONAIS DAS DISTÂNCIAS INTERCANINOS E INTERMOLARES INFERIORES EM TRÊS MOMENTOS

O propósito desse estudo foi de avaliar a estabilidade do tratamento ortodôntico em três momentos distintos, por meio de mensuração das distâncias intercaninos e intermolares inferiores, utilizando, como ferramenta, modelos virtuais tridimensionais. Foram selecionados modelos de gesso da arcada inferior de 19 pacientes em três fases distintas: pré-tratamento (T1), pós-tratamento (T2) e mínimo de 5 anos pós-contenção (T3), totalizando 57 modelos, os quais foram digitalizados por meio do Scanner 3D SCANTEH ST500 (SCAN technology A/S, Dinamarca), para obtenção dos modelos virtuais tridimensionais. Nesses modelos virtuais tridimensionais foram selecionadas e mensuradas as distâncias entre as pontas de cúspide dos caninos, denominada distância intercaninos e pontas de cúspide mesiovestibulares dos primeiros molares, denominada distância intermolares, com o auxílio do programa Rapidform ( Inus Technology Inc,). Para a análise estatística, foi realizada a análise de variância de medidas repetidas, e realizadas comparações múltiplas de Bonferroni ao nível de significância de 5%. As distâncias intercaninos e intermolares, em média, diminuíram entre T1-T2 e continuaram diminuindo entre T2- T3. Após 4 semanas, 20% da amostra foi novamente mensurada para avaliação do erro do método, onde foram encontrados valores médios semelhantes aos encontrados na primeira mensuração. Nesse trabalho, utilizando-se modelos virtuais tridimensionais, nota-se que não há estabilidade durante e após o tratamento ortodôntico, no tocante às distâncias intercaninos e intermolares.

Mantle dynamics and seismic tomography

Three-dimensional imaging of the Earth's interior, called seismic tomography, has achieved breakthrough advances in the last two decades, revealing fundamental geodynamical processes throughout the Earth's mantle and core. Convective circulation of the entire mantle is taking place, with subducted oceanic lithosphere sinking into the lower mantle, overcoming the resistance to penetration provided by the phase boundary near 650-km depth that separates the upper and lower mantle. The boundary layer at the base of the mantle has been revealed to have complex structure, involving local stratification, extensive structural anisotropy, and massive regions of partial melt. The Earth's high Rayleigh number convective regime now is recognized to be much more interesting and complex than suggested by textbook cartoons, and continued advances in seismic tomography, geodynamical modeling, and high-pressure–high-temperature mineral physics will be needed to fully quantify the complex dynamics of our planet's interior.